System and method for attaching soft tissue to bone

ABSTRACT

A system and method for attaching soft tissue to bone is provided. In general, the apparatus includes an expandable body that is configured to expand into bone, and an expander pin that is adapted to be driven into the expandable body. The device can also include a tissue attachment apparatus that can be used to secure tissue to the device, thereby providing a method for attaching tissue to bone.

REFERENCE TO PRIOR PATENT APPLICATION

This is a continuation of prior application Ser. No. 09/360,475, nowU.S. Pat. No. 6,319,252, filed Jul. 23, 1999 by Dennis McDevitt et al.for SYSTEM AND METHOD FOR ATTACHING SOFT TISSUE TO BONE.

FIELD OF THE INVENTION

This invention relates generally to medical devices and procedures. Moreparticularly, this invention relates to systems and methods forattaching soft tissue to bone.

BACKGROUND OF THE INVENTION

The complete or partial detachment of ligaments, tendons and/or othersoft tissues from their associated bones within the body are relativelycommonplace injuries, particularly among athletes. Such injuries aregenerally the result of excessive stresses being placed on thesetissues. By way of example, tissue detachment may occur as the result ofan accident such as a fall, over-exertion during a work-relatedactivity, during the course of an athletic event, or in any one of manyother situations and/or activities.

In the case of a partial detachment, the injury will frequently healitself, if given sufficient time and if care is taken not to expose theinjury to further undue stress.

In the case of complete detachment, however, surgery may be needed tore-attach the soft tissue to its associated bone or bones.

Numerous devices are currently available to re-attach soft tissue tobone. Examples of such currently-available devices include screws,staples, suture anchors and tacks.

In soft tissue re-attachment procedures utilizing screws, the detachedsoft tissue is typically moved back into its original position over thebone. Then the screw is screwed through the soft tissue and into thebone, with the shank and head of the screw holding the soft tissue tothe bone.

Similarly, in soft tissue re-attachment procedures utilizing staples,the detached soft tissue is typically moved back into its originalposition over the bone. Then the staple is driven through the softtissue and into the bone, with the legs and bridge of the staple holdingthe soft tissue to the bone.

In soft tissue re-attachment procedures utilizing suture anchors, ananchor-receiving hole is generally first drilled in the bone at thedesired point of tissue re-attachment. Then a suture anchor is deployedin the hole using an appropriate installation tool. This effectivelylocks the suture to the bone, with the free end(s) of the sutureextending out of the bone. Next, the soft tissue is moved into positionover the hole containing the deployed suture anchor. As this is done,the free end(s) of the suture is (are) passed through or around the softtissue, so that the free end(s) of the suture reside(s) on the far(i.e., non-bone) side of the soft tissue. Finally, the suture is used totie the soft tissue securely to the bone.

Alternatively, in some soft tissue re-attachment procedures utilizingsuture anchors of the type described above, the soft tissue may first bemoved into position over the bone. Then, while the soft tissue lies inposition against the bone, a single hole may be drilled through the softtissue and into the bone. Next, a suture anchor is passed through thesoft tissue and deployed in the bone using an appropriate installationtool. This results in the suture anchor being locked to the bone, withthe free end(s) of the suture extending out of the bone and through thesoft tissue. Finally, the suture is used to tie the soft tissue securelyto the bone.

In some cases, the suture anchor may include drill means at its distalend, whereby the suture anchor can be drilled into the bone, or drilledthrough the soft tissue and into the bone, whereby the aforementioneddrilling and anchor-deployment steps are effectively combined.

Similarly, in soft tissue re-attachment procedures utilizing tacks, thedetached soft tissue is typically moved back into its original positionover the bone, and then a tack-receiving hole is generally drilledthrough the soft tissue and into the bone. Then the tack is driventhrough the soft tissue and into the bone, so that the shaft and head ofthe tack will hold the soft tissue to the bone.

While systems and method based on the aforementioned screws, staples,suture anchors and tacks are generally effective, they also all sufferfrom one or more disadvantages.

OBJECTS OF THE INVENTION

Accordingly, one object of the present invention is to provide a novelsystem and method for re-attaching soft tissue to bone which improvesupon the prior art devices and techniques discussed above.

Another object of the present invention is to provide a novel system andmethod for re-attaching soft tissue to bone which is easy to use andsimple to perform.

And another object of the present invention is to provide a novel systemand method for re-attaching soft tissue to bone which expedites andfacilitates the re-attachment procedure.

Still another object of the present invention is to provide a novelsystem and method for re-attaching soft tissue to bone which minimizestrauma to the patient during the re-attachment procedure.

Yet another object of the present invention is to provide a novel systemand method for re-attaching soft tissue to bone which can be used inboth open surgical procedures and in closed surgical procedures (e.g.,arthroscopic or endoscopic surgical procedures) where access to thesurgical site is provided by one or more cannulas.

And another object of the present invention is to provide a novel systemand method for re-attaching soft tissue to bone which is also usable inthe attachment of prosthetic devices, and/or grafts of natural and/orsynthetic material, to bone or bone-like structures.

SUMMARY OF THE INVENTION

These and other objects of the present invention are achieved by theprovision and use of a novel system and method for attaching soft tissueand the like to bone.

In one preferred embodiment, the novel system comprises an expandablebody configured to expand into bone, the expandable body defining abore; and an expander pin comprising a shaft sized to be received in thebore of the expandable body and expand the expandable body laterallywhen the expander pin is driven into the expandable body, and tissueattachment apparatus associated with the shaft, the expander pindefining a bore; whereby when the expander pin is driven into theexpandable body, the expandable body will be attached to bone and thetissue attachment apparatus will secure tissue to the apparatus.

In one preferred embodiment, the novel method comprises driving anexpandable fastener into a bone, the expandable fastener defining a boreand comprising tissue attachment apparatus; and fixing the expandablefastener in, and thereby securing the tissue relative to, the bone.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIG. 1 is a side view of a novel fastening system formed in accordancewith the present invention;

FIGS. 2-4 are perspective views of the distal end of the fasteningsystem shown in FIG. 1;

FIG. 5 is a side view, partially in section, of the distal end of thefastening system shown in FIG. 1;

FIG. 6 is an exploded view showing the fastener, and a portion of theinstallation tool, of the fastening system shown in FIG. 1;

FIGS. 7 and 8 are perspective, exploded views of the elements shown inFIG. 5;

FIGS. 9-11 show details of the distal tip member of the fastener shownin FIG. 5;

FIGS. 12 and 13 show details of the proximal main member of the fastenershown in FIG. 5;

FIGS. 14-16 show details of the expander pin of the fastener shown inFIG. 5;

FIGS. 17-19 show details of the pusher member of the installation toolshown in FIG. 5;

FIG. 20 is an exploded side view of the handle assembly of theinstallation tool shown in FIG. 1;

FIGS. 21-25 show the novel fastening system of the present inventionbeing used to attach soft tissue (or the like) to bone;

FIGS. 26-28 illustrate one preferred form of the novel fastening systemof the present invention being used to attach soft tissue (or the like)to bone;

FIGS. 29 and 30 illustrate another preferred form of the novel fasteningsystem of the present invention being used to attach soft tissue (or thelike) to bone;

FIG. 31 is a side view showing an alternative form of proximal mainmember for a fastener formed in accordance with the present invention;

FIG. 32 is a side view showing an alternative form of distal tip memberfor a fastener formed in accordance with the present invention;

FIGS. 33-35 show details of an alternative form of the fastener'sexpander pin;

FIGS. 36-38 show details of another alternative form of the fastener'sexpander pin;

FIGS. 39-42 show details of the construction of an alternative form offastener also formed in accordance with the present invention;

FIGS. 43 and 44 show the fastener of FIGS. 39-42 being used to attachsoft tissue (or the like) to bone;

FIG. 45 shows details of an alternative form of expander pin for thefastener shown in FIGS. 39-44;

FIGS. 46-49 show details of the construction of another alternative formof fastener also formed in accordance with the present invention;

FIGS. 50-53 show the fastener of FIGS. 46-49 being used to attach softtissue (or the like) to bone;

FIG. 54 shows details of an alternative form of expander pin for thefastener shown in FIGS. 46-53; and

FIGS. 55 and 56 show details of a removal tool for removing a fastenerformed and deployed in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Looking first at FIG. 1, there is shown a fastening system 5 forattaching soft tissue (or the like) to bone. Fastening system 5generally comprises a fastener 10 and an installation tool 15.

Looking next at FIGS. 1-8, fastener 10 generally comprises an expandablebody 100 (FIG. 2) and an expander pin 200.

Expandable body 100 comprises a generally frusto-conical distal end 105(FIG. 5) characterized by a frusto-conical outer surface 110 terminatingin a distal end surface (or rim) 115, and a generally cylindricalproximal end 120 terminating in a proximal end surface 125. A centralpassageway 130 extends through expandable body 100, from distal endsurface 115 to proximal end surface 125.

In a preferred form of the invention, central passageway 130 comprises abore 135 opening on distal end surface 115, a threaded section 140, anda bore 145 opening on proximal end surface 125.

Expandable body 100 preferably also comprises bone securement apparatus150 formed on proximal end 120 for facilitating securement of fastener 5to bone, as will hereinafter be discussed in further detail. In onepreferred form of the invention, bone securement apparatus 150 comprisesa plurality of frusto-conical ribs 155. Ribs 155 are tapered,distally-to-proximally, so as to (1) facilitate insertion of expandablebody 100 into bone in a distal direction, and (2) resist withdrawal ofexpandable body 100 from bone in a proximal direction.

If desired, expandable body 100 can be formed out of a single piece ofmaterial. Preferably, however, and looking now at FIGS. 1-13, expandablebody 100 comprises a distal tip member 160 (FIG. 9) and a proximal mainmember 165 (FIG. 12).

Distal tip member 160 (FIGS. 9-11) preferably comprises theaforementioned frusto-conical outer surface 110, distal end surface (orrim) 115, internal bore 135, and threaded section 140. Distal tip member160 also preferably comprises a proximally-extending, threadedprojection 170. Proximally-extending threaded projection 170 serves tosecure distal tip member 160 to proximal main member 165, as willhereinafter be discussed in further detail.

Proximal main member 165 (FIGS. 12 and 13) preferably comprises theaforementioned proximal end surface 125, bore 145 and bone securementapparatus 150 (preferably in the form of frusto-conical ribs 155).Proximal main member 165 also comprises a threaded counterbore 175 atits distal end. Threaded counterbore 175 is sized and shaped so as tomatingly receive proximally-extending threaded projection 170 of distaltip member 160, whereby the two elements may be secured to one anotherso as to form the complete expandable body 100.

A primary advantage of forming expandable body 100 out of two separatecomponents (i.e., distal tip member 160 and proximal main member 165) isthat each component can be optimized for its own function. Moreparticularly, inasmuch as distal tip member 160 is intended to help opena passageway in bone to receive the overall fastener 10, distal tipmember 160 is preferably formed out of a relatively hard material. Atthe same time, however, inasmuch as proximal main member 165 is intendedto expand radially outwardly during deployment of the fastener so as tofix expandable body 100 (and hence the complete fastener 10) to bone,proximal main member 165 is preferably formed out a relatively soft andeasily expandable material.

Fastener 10 also comprises the expander pin 200. Looking next at FIGS.1-8 and 14-16, expander pin 200 generally comprises a shaft 205 andtissue attachment apparatus 210 associated with shaft 205. Shaft 205 issized so that it will not normally fit within central passageway 130(FIG. 5) of expandable body 100. However, shaft 205 is also sized sothat when expander pin 200 is driven longitudinally into expandable body100, the expander pin will force the side walls of expandable body 100to expand radially outwardly against adjacent bone, whereby theexpandable body (and hence the entire fastener) will be secured to ahost bone, as will hereinafter be discussed in further detail.

Preferably, shaft 205 includes fastener stabilization apparatus 215 forstabilizing the longitudinal position of expander pin 200 relative toexpandable body 100, as will hereinafter be discussed in further detail.More particularly, fastener stabilization apparatus 215 is adapted toresist withdrawal of expander pin 200 from expandable body 100 onceexpander pin 200 has been driven into expandable body 100, as willhereinafter be discussed in further detail. In one preferred form of theinvention, fastener stabilization apparatus 215 comprises a screw thread220 formed on the outer surface of shaft 205.

Still looking now at FIGS. 1-8 and 14-16, in one preferred form of theinvention, tissue attachment apparatus 210 comprises one or more lateralprojections 225 adjacent to the proximal end of the shaft. The one ormore lateral projections 225 collectively form a fastener head forholding tissue to bone, as will hereinafter be discussed in furtherdetail.

Expander pin 200 includes a longitudinal passageway 230 extending thelength of the expander pin.

Fastener 10 is intended to be used in conjunction with installation tool15. Looking next at FIGS. 1-8, installation tool 15 comprises a shaft300 (FIG. 6) terminating in a tapered distal point 310. Tapered distalpoint 310 is preferably formed so as to be relatively hard; whereby itcan open a passageway in bone to receive the overall fastener 10, aswill hereinafter be discussed in further detail. Threads 315 are formedon shaft 300 proximal to tapered distal point 310. Shaft 300 is sized sothat it may be received in the central passageway 130 (FIG. 5) ofexpandable body 100, and in longitudinal passageway 230 (FIG. 16) ofexpander pin 200. Threads 315 of shaft 300 are sized and positioned sothat when fastener 10 (i.e., expandable body 100 and expander pin 200)is mounted on shaft 300, shaft threads 315 can mate with the expandablebody's threads 140, whereby expandable body 100 can be secured to thedistal end of shaft 300. In one preferred form of the invention, theshaft's tapered distal point 310 and the expandable body'sfrusto-conical outer surface 110 (FIG. 9) are coordinated with oneanother so that when expandable body 100 is screwed onto shaft 300, theexpandable body's frusto-conical outer surface 110 will form, in a roughsense, a continuation, or extension, of the taper of the shaft's tapereddistal point 310 (FIG. 5).

Preferably, the installation tool's shaft 300 comprises a thinner distalsection 320 (FIG. 5) proximal to the shaft's tapered distal point 310and distal to the shaft's threads 315, and a trailing section 325proximal to shaft threads 315, and a thicker proximal section 330proximal to trailing section 325. Trailing section 325 and thickerproximal section 330 together define an annular shoulder 335 at theirintersection. A rib 340 is preferably formed on trailing section 325,distal to annular shoulder 335.

A pusher 400 (FIGS. 5 and 17) is preferably mounted on shaft 300. Pusher400 is used to help deploy fastener 10 in bone, by transferring a forceapplied to the proximal end of pusher 400 onto a fastener 10 located atthe distal end of pusher 400. In the process, pusher 400 acts as a sortof safeguard to prevent the proximal end of fastener 10 (i.e., theproximal end of expander pin 200) from being damaged during theapplication of such force. Pusher 400 preferably comprises a tapereddistal portion 405 characterized by a tapered outer surface 410terminating in a distal end surface 415, and a cylindrical proximalportion 420 characterized by a cylindrical outer surface 425 terminatingin a proximal end surface 427. Pusher 400 has a central bore 430extending therethrough. Bore 430 is sized so that it will form a closesliding fit with rib 340 (FIG. 6) of shaft 300. A lip 435 (FIG. 17)protrudes into central bore 430 adjacent to the pusher's proximal endsurface 427. Lip 435 is sized so that it may not pass by rib 340 ofshaft 300.

In one preferred form of the invention, shaft 300 includes a pluralityof ribs 345 (FIG. 6) on the shaft's thicker proximal section 330, andinstallation tool 15 includes a handle assembly 500 (FIG. 20). Each rib345 includes an inclined surface 345A disposed on the proximal side ofthe rib (FIG. 6). The distal side of each rib 345 extends substantiallyperpendicular to the longitudinal axis of shaft 300.

Handle assembly 500 comprises a body 501 having a handle grip 502. Atrigger 505, having a plurality of fingers 507, is pivotally connectedto body 501. Body 501 also comprises a bore 508 opening on the body'sdistal end, and a counterbore 509 opening on the body's proximal end. Ashoulder 509A is formed at the intersection of bore 508 and counterbore509.

Handle assembly 500 also comprises a hollow ram 515. Ram 515 is sized sothat it can slidably accommodate shaft 300, as will hereinafter bediscussed in further detail. Ram 515 comprises a narrower distal portion520 terminating in a distal tip 510, and a wider proximal portion 525including a plurality of teeth 530. A shoulder 535 is formed at theintersection of narrower distal portion 520 and wider proximal portion525. A slot 540 extends through the side wall of narrower distal portion520.

Ram 515 is mounted in body 510 in the manner shown in FIGS. 1 and 20,i.e., so that (1) the ram's narrower distal portion 520 extends through,and protrudes from, the body's bore 508, (2) the ram's wider proximalportion 525 is disposed in the body's counterbore 509, and (3) thetrigger's fingers 507 engage the ram's teeth 530. As a result of thisconstruction, moving trigger 505 will cause ram 515 to move relative tobody 501. A spring 545 is positioned in body 501, between body shoulder509A and ram shoulder 535, so as to bias ram 515 in a proximaldirection. A stop pin 550 extends into counterbore 509 so as to limitproximal movement of ram 515.

Handle assembly 500 also comprises a gate 555 which includes an opening560 therein. Opening 560 defines a bottom wall 565 thereof. Gate 555 isdisposed in an opening 570 formed in body 501. A spring 575 biases gate555 against a locking pin 580, which extends through an oversized hole585 formed in gate 555. Gate 555 is disposed in body 501 so that thegate's bottom wall 565 normally protrudes, via ram slot 540, into theinterior of ram 515; however, pressing gate 555 downward against thepower of spring 575 will permit the gate's bottom wall 565 to be removedfrom the interior of ram 515.

In use, and as will hereinafter be discussed in further detail, handleassembly 500 is loaded over the proximal end of shaft 300, and movedproximally down the shaft until the gate's bottom wall 565 starts toengage the ribs 345 of shaft 300. As this occurs, the inclined proximalsurfaces 345A of ribs 345 will allow the handle assembly 500 to be moveddistally along shaft 300 to the extent desired. However, since inclinedsurfaces 345A are provided on only the proximal sides of ribs 345, thegeometry of the ribs will prevent handle assembly 500 from moving backproximally along the shaft, unless gate 555 is pressed downward againstthe power of spring 575 so as to move the gate's bottom wall 565 out ofengagement with the shaft's ribs. Handle assembly 500 is moved downshaft 300 until the ram's distal end surface 510 engages, orsubstantially engages, the proximal end 427 of pusher 400. Thereafter,pulling of the handle assembly's trigger 505 will cause ram 515 to movedistally along shaft 300, whereby pusher 400 can drive expander pin 200into expandable body 100 so as to set the expandable body in bone, aswill hereinafter be discussed in further detail.

The use of handle assembly 500 in conjunction with shaft 300 is oftenpreferred, since it permits shaft 300 to be held in-place while ram 515is advanced down shaft 300. More particularly, inasmuch as handleassembly 500 is releasably secured to shaft 300 via the engagement ofhandle gate 555 with shaft ribs 345, handle assembly 500 can stabilizeshaft 300 even as the handle's ram 515 is advancing down shaft 300. Thishas been found to be advantageous in many circumstances. However, itshould also be appreciated that fastener 10 can be set without usinghandle assembly 500, as will hereinafter also be discussed in furtherdetail.

Looking next at FIGS. 21-25, there is shown a general method forattaching soft tissue (or the like) to bone using the fastener of thepresent invention. In particular, the invention will be discussed in thecontext of (1) a fastener 10 comprising an expandable body 100 and anexpander pin 200; (2) an installation tool 15 comprising a shaft 300;and (3) a pusher 400 mounted on shaft 300.

The foregoing fastening system is prepared for use by first passingpusher 400 proximally over the distal end of shaft 300 until thepusher's proximal end surface 427 (FIG. 17) engages, or approximatelyengages, the shaft's annular shoulder 335 (FIG. 6). Then the fastener'sexpander pin 200 is passed proximally over the distal end of shaft 300until the proximal end of expander pin 200 engages, or approximatelyengages, the pusher's distal end surface 415 (FIG. 17). Next, thefastener's expandable body 100 is passed proximally over the distal endof shaft 300 until the proximal end of the expandable body's threadedsection 140 (FIG. 5) engages the distal end of the shaft's threads 315(FIG. 6). Then the fastener's expandable body 100 is screwed onto shaft300. At this point, the proximal end surface 125 (FIG. 12) of expandablebody 100 will engage, or approximately engage, the distal end surface ofexpander pin 200. It will be appreciated that at this point, theexpandable body 100, expander pin 200 and pusher 400 will be heldrelatively immobile on shaft 300, by virtue of shaft shoulder 335 (FIG.6) and shaft threads 315 and the sizing of the elements heldtherebetween.

Next, soft tissue (or the like) 600 is “stabbed” with the sharp distalpoint of shaft 300 and dragged to its desired position against bone 700(FIG. 21). Alternatively, soft tissue 600 may be gripped by anotherinstrument (e.g., forceps or the like) and moved into position againstbone 700.

Then, with soft tissue 600 in position against bone 700, shaft 300 isforced distally through tissue 600 (FIG. 22) and into bone 700 (FIG.23). It will be appreciated that, as this occurs, expandable body 100will be carried into the bone, due to the screw engagement establishedbetween expandable body 100 and shaft 300. In fact, the tapered distalends of shaft 300 and expandable body 100 will cooperate with oneanother so as to force an opening in the soft tissue and the bone,without any need for pre-drilling. Shaft 300 is preferably driven intobone 700 until the proximal end surface 125 of expandable body 100 isapproximately even with the outer surface of bone 700 (FIG. 23). Ifdesired, markings (not shown) may be placed on the outer surface of thefastener's expander pin 200 so that, once the thickness of soft tissue600 is known, proper depth penetration can be achieved.

Next, the proximal end of pusher 400 is engaged with another element(not shown in FIGS. 21-25, but shown in subsequent figures) so as tomove the pusher distally along shaft 300. Pusher 400 is moved distallyso as to drive expander pin 200 distally, into the central passageway130 (FIG. 5) of expandable body 100, whereby to drive the side walls ofexpandable body 100 radially outwardly into bone 700 and thereby securefastener 10 to bone 700 (FIG. 24). At the same time, the fastener'stissue attachment apparatus 210 will secure soft tissue 600 to the bone.More particularly, as seen in FIG. 24, the head of expander pin 200(made up of one or more lateral projections 225) will bear distallyagainst soft tissue 600, whereby to keep the soft tissue fixed againstbone 700.

Finally, shaft 300 is unscrewed from the expandable body's threads 140(FIG. 5) and removed (FIG. 25), leaving fastener 10 securing soft tissue600 to bone 700.

As noted above, in one preferred form of the invention, installationtool 15 is constructed so that shaft 300 includes ribs 345 (FIG. 6)adjacent its proximal end, and the installation tool includes handleassembly 500 (FIG. 20). FIGS. 26-28 illustrate how soft tissue 600 maybe attached to bone 700 using such an arrangement. More particularly,after pusher 400, expander pin 200 and expandable body 100 have beenattached to shaft 300 in the manner described above with respect toFIGS. 21-25, and either before or after shaft 300 is driven through softtissue 600 and into bone 700 to the point shown in FIGS. 23 and 26,handle assembly 500 is passed distally over the proximal end of shaft300 until the gate 555 engages ribs 345 of shaft 300. Handle assembly500 is then pushed further down shaft 300 until the distal tip 510 ofram 515 engages the proximal end of pusher 400. Then trigger 505 isactivated so as to move ram 515 distally relative to pusher 400 andfastener 10, whereby the distal tip 510 (FIG. 20) of the handleassembly's ram 515 will drive distally against the proximal end ofpusher 400. This will cause pusher 400 to move expander pin 200distally, whereby to fix fastener 10 in bone 700, with the fastener'shead fixing soft tissue 600 to bone 700 (FIG. 27). Then handle assembly500 is removed proximally off shaft 300, i.e., by first pressing gate555 downward against the power of spring 575 so as to move the gate'sbottom wall 565 out of engagement with ribs 345, and then pulling thehandle assembly 500 proximally off the shaft. Then shaft 300 isunscrewed from the expandable body's threads 140 and removed from thesurgical site (FIG. 28).

It will be appreciated that, by virtue of the relative sizing of shaftrib 340 (FIG. 6) and pusher lip 435 (FIG. 17), pusher 400 will beslidably retained on the distal end of shaft 300 even after shaft 300has been unscrewed from fastener 10, since pusher lip 435 will be unableto move past shaft rib 340.

As noted above, the use of handle assembly 500 in conjunction with shaft300 is frequently preferred, since it permits shaft 300 to be held inplace while ram 515 is advanced down shaft 300. More particularly,inasmuch as handle assembly 500 is releasably secured to shaft 300 viathe engagement of handle gate 555 with shaft ribs 345, handle assembly500 can stabilize shaft 300 even as the handle's ram 515 is advancingdown shaft 300. In other words, since the fastener's expandable body 100is connected to shaft 300 by the expandable body's threaded section 140and shaft threads 315, and inasmuch as handle assembly 500 is releasablysecured to shaft 300 via the engagement of handle gate 555 with shaftribs 345, the handle assembly can advance its ram 515 against thefastener's expander pin 200 even while the handle assembly is holdingthe shaft 300, and hence the fastener's expandable body 100, in place.In effect, the use of handle assembly 500 in conjunction with shaft 300permits a proximally-directed counterforce to be applied to expandablebody 100 even as a distally-directed setting force is being applied toexpander pin 200.

However, it should also be appreciated that fastener 10 can be setwithout using handle assembly 500, as will hereinafter be discussed infurther detail.

Thus, in another preferred form of the invention, installation tool 15may be constructed so that shaft 300 omits ribs 345 on its proximal end,and so that the installation tool 15 does not include handle assembly500. In this case, pusher 400 may be moved proximally on shaft 300 byother means.

For example, and looking now at FIGS. 29 and 30, a cannulated driver800, such as one having a so-called “slap hammer” configuration, can beused to drive pusher 400 distally on shaft 300, whereby to completesetting of fastener 10 in bone 700.

While the “slap hammer” construction shown in FIGS. 29 and 30 is simpleand effective, it does suffer from the disadvantage that aproximally-directed counterforce is not being applied to expandable body200 even as the distally-directed setting force is being applied toexpander pin 300, as is the case with the use of handle assembly 500described above.

It should be appreciated that, if desired, the expandable body's bonesecurement apparatus 150 (FIG. 12) may be omitted or, alternatively,replaced by a configuration different than the ribs 155 (FIG. 12)previously disclosed. By way of example but not limitation, bonesecurement apparatus 150 may comprise screw threads 155A shown in FIG.31.

It should also be appreciated that, if desired, the expandable body'sdistal end 105 (FIG. 5) may have a configuration other than the smooth,frusto-conical one disclosed above. By way of example but notlimitation, expandable body 100 may have screw threads formed on itstapered distal end. See, for example, FIG. 32, which shows the screwthreads 110A formed on distal tip member 160.

FIGS. 33-35 show an alternative form of expander pin 200. Moreparticularly, the expander pin 200 shown in FIGS. 33-35 is similar tothe expander pin 200 shown in FIGS. 14-16, except that with the expanderpin of FIGS. 33-35, lateral projections 225A have their outlying edges226 rounded into an arc-like configuration.

FIGS. 36-38 show yet another alternative form of expander pin 200. Moreparticularly, the expander pin 200 shown in FIGS. 36-38 is similar tothe expander pin 200 shown in FIGS. 14-16, except that with the expanderpin of FIGS. 36-38, fastener stabilization apparatus 215 comprises aplurality of frusto-conical ribs 220A, rather than the screw thread 220shown in FIGS. 14-16.

It is also possible to form the fastener's tissue attachment apparatus210 with a different configuration (and with a different manner ofoperation) than the tissue attachment apparatus shown in FIGS. 14-16 or33-36.

More particularly, with the tissue attachment apparatus 210 shown inFIGS. 14-16 and 33-36, the tissue attachment apparatus essentiallycomprises a head for capturing the soft tissue to bone. However, it isalso contemplated that tissue attachment apparatus 210 may comprise asuture-based mechanism for capturing the soft tissue to bone.

More particularly, and looking now at FIGS. 39-42, there is shown afastener 10 in which tissue attachment apparatus 210 comprises aplurality of transverse bores 227 formed in expander pin 200 adjacent toits proximal end. Bores 227 accommodate one or more lengths of suture228 (FIG. 39) which may be used to tie a piece of soft tissue (or thelike) to bone. In one preferred form of the invention, expander pin 200includes a cylindrical proximal end portion 229 (FIG. 40) having adiameter larger than the diameter of the central passageway 130 (FIG. 5)of expandable body 100, with transverse bores 227 being formed incylindrical proximal end portion 229.

In use, the fastener is set through soft tissue 600 and into bone 700 inthe normal manner (FIGS. 43 and 44); however, since the fastener lacksthe lateral projections 225 (FIG. 14) previously disclosed, the proximalend of expander pin 200 will pass through soft tissue 600 withoutbinding it to the bone (FIG. 44). However, sutures 228 will extend outof bone 700 and through soft tissue 600. As a result, these sutures maythen be used to tie the soft tissue down to the bone.

If desired, the expander pin 200 shown in FIGS. 39-44 can be modified soas to have its fastener stabilization apparatus 215 in the form of ribs220A (FIG. 45), rather than the screw thread 220 shown in FIG. 40.

With respect to the fastener configuration shown in FIGS. 39-45, itshould be appreciated that by positioning transverse bores 227 (FIG. 40)in the diametrically-enlarged proximal end portion 229, the transversebores 227 will remain proximal to expandable body 100 even after settingof the fastener (FIG. 44). As a result of this construction, sutures 228will be able to slip within bores 227 even after fastener 10 has beencompletely deployed in bone 700. As will be apparent to persons skilledin the art, this can be advantageous in some circumstances during tissuefixation.

It is also possible to fabricate a fastener 10 with a suture-basedmechanism for capturing soft tissue to bone, but where the sutures areprevented from slipping relative to the fastener once the fastener hasbeen fully deployed in the bone.

More particularly, and looking now at FIGS. 46-49, there is shown afastener 10 which includes an expander pin 200 having a plurality oftransverse bores 227 intermediate its length (FIG. 47). Bores 227accommodate the one or more lengths of suture 228 which may be used totie a piece of soft tissue (or the like) to bone. In one preferred formof the invention, expander pin 200 includes a cylindrical intermediateportion 229A (FIG. 47) having a diameter substantially the same as theremainder of the expander pin, with transverse bores 227 being formed inthe cylindrical intermediate portion 229A.

Looking next at FIGS. 50-53, in one preferred method of use, shaft 300and expandable body 100 are driven into bone, and then a piece of suture228 is looped around the soft tissue 600 which is to be attached to thebone 700 (FIG. 50). Then the suture 228 is pulled taut so as to bringthe soft tissue into close proximity to the fastener (FIG. 51). Thenpusher 400 is driven distally (FIG. 52) so as to completely set thefastener. At this point, since suture 228 is attached to expander pin200 intermediate the length of the expander pin, the suture will befixed in place relative to the deployed expander pin and, hence, willsecure soft tissue 600 to bone 700. Installation tool 15 is then removedfrom the surgical site by unscrewing shaft 300 from expandable body 100(FIG. 53).

If desired, expander pin 200 can also be formed so that itssuture-receiving bores 227 are located adjacent to the distal end of theexpander pin. For example, in another preferred form of the invention,expander pin 200 includes a cylindrical distal end portion 229B (FIG.54) having a diameter substantially the same as the remainder of theexpander pin, with transverse bores 227 being formed in the cylindricaldistal end portion.

Looking next at FIGS. 55 and 56, there is shown a removal tool 800.Removal tool 800 can be used to remove a previously-deployed fastener10, if the same should prove necessary or desirable. Removal tool 800generally comprises a shaft 805 having a reverse thread 810 formed onits distal end and a handle 815 formed on its proximal end. The distalend of removal tool 800 is sized so as to be significantly larger thanthe longitudinal passageway 230 (FIG. 16) formed in expander pin 200.

When a previously-deployed fastener 10 is to be removed, the distal endof removal tool 800 is screwed into the proximal end of expander pin 200using the removal tool's reverse screw thread 810. Inasmuch as thedistal end of the removal tool is significantly larger than thelongitudinal passageway 230 formed in expander pin 200, this action willcause the removal tool's distal threads 815 to force their way into theside wall of expander pin 200 and, depending on the sizing of theremoval tool, possibly into the side wall of expandable body 100 aswell. In any case, as the reverse thread 810 of the removal tool isscrewed into the expander pin, continued reverse screwing willeventually cause the normally-threaded expander pin 200 to unscrewitself from expandable body 100. Removal tool 800 may then be used toremove expander pin 200 from expandable body 100. Expandable body 100may then itself be removed from the surgical site by passing shaft 300back into the interior of expandable body 100, screwing the shaft'sthreads 315 into the expandable body's threaded section 140, and thenremoving the shaft and expandable body from the bone.

What is claimed is:
 1. An apparatus for attaching tissue to bone,comprising: an expandable body including a proximal portion and a distaltip portion that is separable from the proximal portion, the expandablebody having a bore extending therethrough; and an expander pin sized tobe disposed within the bore in the expandable body such that theexpander pin is effective to expand the expandable body, the expanderpin including a tissue attachment apparatus formed thereon.
 2. Theapparatus of claim 1, wherein the proximal portion and the distal tipportion are threadably matable with one another.
 3. The apparatus ofclaim 1, wherein the proximal portion and the distal tip portion arefrictionally engageably with one another.
 4. The apparatus of claim 1,wherein the distal tip portion of the expandable body is formed from afirst material, and the proximal portion is formed from a secondmaterial, the first material being harder than the second material. 5.The apparatus of claim 1, wherein the tissue attachment apparatuscomprises at least one bore formed in the expander pin for receiving atleast one suture therethrough.
 6. An apparatus for attaching tissue tobone, comprising: an expandable body having a bore extendingtherethrough; an expander pin sized to be disposed within the bore inthe expandable body such that the expander pin is effective to expandthe expandable body, the expander pin including a tissue attachmentapparatus formed thereon, and a bore extending therethrough; and aninstallation shaft adapted to be received in the bore in the expandablebody and in the bore in the expander pin, the shaft being matable to theexpandable body.
 7. The apparatus of claim 6, wherein the installationshaft and the expandable body are threadingly interengageable with oneanother.
 8. The apparatus of claim 6, further comprising a pusher memberadapted to drive the expander pin into the expandable body.
 9. Theapparatus of claim 8, wherein the pusher member is slidably disposedaround the installation shaft.
 10. An apparatus for attaching tissue tobone, comprising: an expandable body having a bore extendingtherethrough; an expander pin adapted to be disposed within the bore inthe expandable body to expand the expandable body, the expander pinincluding a tissue attachment apparatus formed thereon, and a boreextending therethrough; and an installation shaft disposable within thebore in each of the expandable body and the expander pin, the shaftincluding a tapered distal end.
 11. The apparatus of claim 10, whereinthe expandable body includes a generally frusto-conical distal end forseating a distal end portion of the installation shaft.
 12. An apparatusfor attaching tissue to bone, comprising: an expandable body having abore extending therethrough; an expander pin adapted to be disposedwithin the bore in the expandable body to expand the expandable body,the expander pin including a tissue attachment apparatus formed thereon,and a bore extending therethrough; and an installation shaft slidablydisposed through the bore in the expander pin and the bore in theexpandable body such that a distal end of the shaft extends distallybeyond the expandable body.